Version info: All this is based on the original game (patch 1.21g), which is all that's available for the Mac. I'll be pissed if they don't port Conquests...
In Civ2, it paid to be constantly at war-- indeed, it was the only way to keep the other civs off your turf. Civ3, by contrast, rewards long periods of peace, punctuated with bursts of short, well-planned warfare. Too much war tires out the populace, while peace alone (despite the new victory conditions) will leave you too small to compete.
In many ways the designers have discouraged war-- but it's hard to win (by any method) unless you're big. Bigness means more science, more production, and more money; it (usually) discourages the other civs' aggression; it gives you better chances at having resources and luxuries; and last but not least, it means territory interdiction-- land you own is land your rivals can't use. And you really can't get big without fighting a few wars.
Ideally you'll have a territory you can easily expand into... it's a real pain to be crushed into a small space between massive rivals, just as it's a real pleasure to have an outback you can easily get to and they can't. Naturally you want to grab the spots with good resources first. (Techs that reveal them, such as Iron Making, The Wheel, and Gunpowder, are important-- though you'd go for those anyway because of the units.)
As in Civ2, the best terrain is grassland with a smattering of hills and forests. Plains are fine (the extra shields can be key, but without as much food the cities won't grow as fast). Tundra is awful, especially since it can't be converted into something else. Jungle can be cleared, but it takes so long that if your region is mostly jungle you'd might as well restart. Ditto if you have no fresh water; it takes too long (till Electricity) to get the ability to irrigate without it.
Settle next to rivers where possible; it'll save you the cost of an Aqueduct. And make sure one of your first cities is on the ocean, so you can try for the Colossus.
Best of all, the AI is not that great at the culture war. If you simply build a Temple and Library in every city, you'll be ahead in culture. (If you're Scientific or Religious, you'll get a hefty discount on their production cost.)
If you're ahead, you'll probably get some nice culture flips-- one reason not to worry much about little cities the other civs sneak in at the edges of your region. (Note that cities won't flip unless some of their theoretical 2-square radius is in your territory. So go build right next to them and culture-bomb 'em.)
You do have to worry when taking over another civ's cities. As the military advisor says, put "strong units" in there (come to think of it, I've never had any trouble sending in "weak units" instead)-- but this alone is apparently only the least of the factors the game considers. Build a temple-- rush-build it if you can. Keep the city out of civil disorder. The city is only really safe when the citizens belong to your culture; so consider making workers or letting it starve for awhile.
If you've just captured a big, wonderless city full of resisters, and you're short on defenders or just want to use your army to keep attacking, then you might want to raze the city. This goes against the Civ2 grain, where cities are Always Good; but you may do better just to rush over a Settler and rebuild. Razing tends to piss off the other civ, so you might want to keep the city if you were hoping to make peace soon.
|Bronze Working||if you didn't start with it|
|Literature||need those libraries!|
|Monarchy||for the better production|
|Banking||you want banks and Wall Street|
|Military Tradition||for Cavalry|
|Replaceable Parts||for Infantry|
|Mass Production||for Tanks|
In medieval times, once you have Gunpowder, it's probably best to head straight for Democracy-- you need it to speed up science and improve production, you don't want to go long without Banks and Universities, and you want to be able to try for Cope's and Newton's.
However, an alternative is to get Military Tradition first. If you have Cavalry and your rivals don't, you can whittle them down a bit.
As you approach gaining a tech, check the City Advisor screen every turn. Usually you can ratchet down science a turn or two early, getting the tech in the same number of turns but getting a windfall of cash. (So far as I can see, unused beakers don't apply to the next tech anyway.)
The first point is easy: sell your extra luxuries. At first, civs will be willing to trade resources even, or even pay you something extra; later they turn miserly and even insane. Still, better to take what they'll give than get nothing for them.
Same for strategic resources, except that you want to be careful about giving your bigger rivals what they need. If a big, nearby civ needs saltpeter, good, let them suffer. (If they're far away, however, let them empty their treasury in your direction!)
Second, tirelessly whore out your science. Whenever you get an advance, peddle it to every civ who doesn't have it. Especially at the beginning, you may get an extra advance that way-- repeat the process. The AI particularly likes certain techs-- often, those leading up to a good wonder-- and it'll pay a good price for them. (The Romans recently gave me 1400 gold for Atomic Theory.)
Again, you may sometimes want to hold back on key techs (e.g. Gunpowder, Democracy, Replaceable Parts). But balance this with the fact that they'll get it on their own sooner or later; why not at least make a buck off them?
Don't forget to haggle. Sometimes the AI is bluffing; you can almost always negotiate a better deal. (Hint: your advisor never lies about whether they'll accept a deal. He can be pretty far off about how close the deal is, however.) If the AI suggests "trading maps" with a little tech snuck in, what they really want is the tech; clear the table and see what they'll offer for it alone.
A short-circuit: suppose you want a tech. Ask what they want for it-- perhaps they want a tech and a resource. Clear their side of the table and see what they'll give for those things. You may be pleasantly surprised how much more they'll offer.
No matter what they're after, I don't like to send them home empty-handed. Any trade at all, even of world maps, makes them like you at least a bit. (However, some players say never to give your map away, so the other civs won't settle free spots in your area. In my experience, however, they will anyway.)
Peace negotiations are fun if you're way ahead: you can get money, techs, even resources and small cities. If I'm losing, I'll pay some money to get out of a war, but if the demands are exorbitant it's usually better to struggle on. (In a recent game, the English went from demanding an entire city as the cost of peace, to being willing to give up money and techs for it, after the loss of a single city.)
Demands for tribute are a gamble-- half the time they're bluffing... unless you're quite weak, in which case they're very serious. Early in the game it's not hard to be flush with cash compared with the AI, and you may want to give in just to keep them off your back while you develop. You can always attack them later, at a time of your choosing.
There's a lot to be said for not finishing off rivals. A tiny civ will never be a threat, and they'll pay through the nose for techs.
At the middle levels, it seems like everybody gets their first Wonder. I usually go for the Colossus or the Pyramids, but I'm never upset to end up with the Hanging Gardens or Sun Tzu's.
Given the anti-war leanings of Civ3, it's odd that the only way to speed up a wonder is via Leaders, which you can only get through war. I always use them for Wonders-- Armies are fun to try out, but I think they're less effective than the component units alone. Their attack is stronger, but they can only kill one unit between them.
About all you can do to help Wonder production is make sure shield production is high in your capital and a few other cities. Build mines (don't neglect Mountains) and put roads and railroads through them; build factories and if possible Hoover's Dam; don't neglect irrigation, since size helps too.
About the only available trick is to start building a Palace somewhere, well before you get the tech for the target Wonder; when you get it, switch.
I still try to follow the Super Science City strategy, but it's harder in Civ3 since you can't get Copernicus till the late middle ages-- rather close to Newton's. This is just a very odd decision on the part of the designers; another is a growth Wonder (Longetivity) that comes just before the game ends.
You want to make sure that this isn't you. In Civ2 the AI never understood that a city was well-defended; in Civ3 it seems to always know where your forces are. Not only will it respect you if your cities brim with defenders (at least four, but to discourage a strong rival a dozen isn't too many); if it does attack, it will hone in on that one city you left with just one Swordsman.
If they're all dogpiling on someone else, join in and pick up some easy cities. Or just go in with some settlers and claim the vacated land-- something the AI is weak on.
War weariness is a killer in Civ3. In general Democracy is the best government in Civ3-- no Senate, best science-- but your citizens hate wars that last more than (say) ten or fifteen turns. Communism is better for this, and it's about the only way to quickly develop a conquered area far from your homeland; but the anarchy between governments is a real pain, unless you're Religious.
A recent game has made me think more kindly of Republics. Science is much better than under Communism (it was only marginally better in Civ2), and war weariness is better than Democracy. In this (Monarch) game I forgot to change to Democracy, and still got into space as a Republic.)
So, plan on bursts of war followed by periods of consolidation. You can often wipe out a substantial rival in three wars.
You can never have too many units, especially by Civ2 standards. For a recent campaign, I made sure I had six Cavalry for each enemy city I wanted.
Civ3 tossed the Civ2 idea of firepower, replacing it with extra attack/defense points; the general effect is to make units seem wimpier. In Civ2 a Pikeman was no match for Cavalry; in Civ3 the advantage is noticeably slimmer.
You'll have to completely re-learn how to use artillery. Neither artillery nor ships can totally take out a unit in Civ3-- they can only reduce it to 1 hit point-- which at first seems to make them useless. However, a huge stack of artillery-- say, 15 or 20 of them-- is an enormous asset. I've used such a stack to reduce one of the Civ3 AI's huge stacks of invading armies; Cavalry can be used to mop up the 1-hp survivors. Once you have railroads, the artillery stack is in effect available anywhere you need it. You can even use it to reduce incoming ships-- though you'll need your own naval forces to eliminate the survivors. (You can destroy a 1-hp Battleship with a mere Ironclad.)
Artillery is harder to use on offense, until you get the actual Artillery unit, which can bombard from two spaces away. Back it up with strong defensive units-- maybe even build a city two spaces away from your target. It pays to batter away at a city with artillery and air/naval support before sending in the troops. (Remember that if you can get a city below 12 or 6 citizens, it loses a significant defense bonus.) Don't stop building Artillery once you have Bombers: Artillery can't be shot down.
The AI will use its artillery to attack your resources and terrain improvements. You can do the same to it (it's great if you can deny it the use of its only horse or saltpeter), but it seems a little short-sighted if it's land you want to keep for yourself.
It can be frustrating to meet your war aims, face growing war weariness, and find that the AI won't negotiate. This is another reason to prepare lots of forces before the war and not to overreach while fighting: you can often get past the unwillingness to negotiate by taking another small city or two, or even by threatening to, and to do that you'll need free units.
It can be unwise to provoke a huge rival till you can wield a larger force; but it can pay off to grab some small, remote cities, then ask for peace. Sometimes the loss seems to demoralize the AI, and it'll make peace and even pay for the privilege. I've also found that if you can survive the AI's initial attack and destroy its huge stacked army, it may be quite vulnerable to a counterattack. (The AI is also not so good at naval warfare: even a very large civ has trouble mobilizing an effective attack on another continent.)
Allies are a mixed bag. They can actually be useful (unlike in Civ2); it's a good way to attack a large rival (and for that matter neutralize your ally), and a timely alliance can keep other civs from picking on you. On the other hand, a mutual protection pact can drag you into or prolong wars you don't want. The ideal really is to be enormous enough to have no alliances. (Second-best: sign an MPP with your largest rival. If you sign with the third-largest civ, #2 may attack #3, dragging you into the war on the wrong side.)
Civ3 espionage seems like a failed afterthought. It's absurdly difficult to successfully place a spy; and then it's just randomness. The spirit of Civ, to me, is the ability to marshal your own forces, not to roll dice.
I prefer the religious, scientific, commercial, and industrious attributes, in about that order. Religion lets you switch governments at will and makes it easy to build temples for fast culture accumulation. You need all the help you can get in science. And the other two are nice bonuses. I haven't seen that much of an payoff to expansionist or militaristic attributes. (Scouts are wimps who can't knock off barbarians; and cheap barracks are a poor substitute for cheap temples or libraries.)
The best unique units are those that offer added defense, and don't come either too early or too late in the game. Hoplites and Legions both offer a defense of 3, which is extremely valuable early on-- it's like getting Pikemen an age early. On the other hand it's hard to win a battle with Hoplites (attack strength 1), which you want to do to start your Golden Age. (Either get started very early, or use a Hoplite to eliminate a weak defender who's already at 1 hp.)
For general aggression my favorites are the Immortals, which offer a 33% attack bonus relative to the other civs, as well as the best timing-- you can get that size edge very early in the game. Elephants and Riders provide a nice boost early in the medieval era.
Most of the other unique units are either unexciting, or come too early or late in the game to help much.
So, overall, I probably play most often as the Greeks, Indians, Persians, Babylonians, or Chinese.
(In my best game, I managed to get the Colossus; but there wasn't any iron anywhere nearby, so I couldn't build any Immortals. Bad luck; but surely the gurus can deal even with that.)
This just in: If you want a lasting advantage, try for early war-- the earlier the better. In the right circumstances, you can take some cities with three or four Elite Warriors. If not, wait till you have half a dozen Archers or Swordsmen. You may not be able to eliminate a civ-- and you don't have to. But you'll have more cities, a larger area to expand into, and a weak neighbor who can serve as a buffer or as a buffet. It's enough to make Monarch, at least, go pretty smoothly.
Latest notes: I've come in from behind often enough that I'm starting to see the AI's weaknesses. Often I've taken on a rival who (as I see at the end in the replay) was twice as big as me, or more. In the early game, the AI isn't good at leveraging its bulk, and it's vulnerable to a very strong attack on a weak spot.
The AI can also be inexcusably bad at the space race. I've beaten it a few times that seem almost inexplicable-- unless its priorities are not quite right. I don't think it knows the build-a-palace trick, for instance, and it seems to prefer to make armies with its Leaders. It's also fractionally less eager to build Hoover's Dam, and you can take advantage of this.